/**

* Write a program to sum up the individual digits of a positive integer,

* given in the command line. The output shall look like:

*

* > java SumDigits 12345

* The sum of digits = 1 + 2 + 3 + 4 + 5 = 15

*/

package javaexercises.cmdline;

public class SumDigits {

public static void main(String[] args) {

SumDigits aSumDigits = new SumDigits();

if (args.length == 0) {

System.out.println("There are no arguments.");

return;

}

try {

int number = Integer.parseInt(args[0]);

if (number < 0) {

System.out.printf("Argument \"%1$s\" is not a positive integer \n", args[0]);

return;

}

aSumDigits.run(number);

}

catch (NumberFormatException e) {

System.out.printf("Argument \"%1$s\" is not an integer \n", args[0]);

}

}

/**

*

*/

private void run(int number)

{

String tmp = String.valueOf(number);

int sum = 0;

System.out.print("The sum of digits = ");

for (int i = 0; i < tmp.length(); i++) {

sum += Character.digit(tmp.charAt(i), 10);

System.out.print( (i == 0 ? "" : " + ") + tmp.charAt(i));

}

System.out.print(" = " + sum + "\n");

}

}